Deodorants are traditionally used to reduce or eliminate body odor caused by the breakdown and fermentation of secretions from apocrine sweat glands. Gram positive bacteria such as Corynebacterium xerosis, and Staphylococcus epidermis are primary examples of odor causing bacteria that inhabit human skin. Many commercially available deodorants help to eliminate body odor by acting as a bactericide or bacteriostat. Bactericides kill bacteria while bacteriostats inhibit the growth of bacteria.
Commercially available underarm deodorants are available in several formats for application to the underarm area. Among these formats are aerosol, pump spray, roll-on, deodorant pads and stick applicators. Stick applicators are the most popular format followed by aerosols and pump sprays.
Stick applicators are essentially made of a solid or semi-solid material (i.e., a base composition that is firm to the touch) impregnated with ingredients that function to kill bacteria or limit their growth, fragrances, stabilizers, moisturizers, etc. To use the stick applicator, the user swipes the stick applicator in the armpit one or more times thereby coating the underarm with a thin layer of the deodorant material. As would be expected, there are characteristics that make some carrier materials superior to others. For example, product hardness, moisture content, stickiness, oiliness, wetness, easy by which the deodorant material goes on to the underarm (payout) and ease of application (e.g., how much pressure does the user have to use to deposit the required amount of deodorant material to the underarm referred to herein as “glide”), the ability of the deodorant material to stay on the underarm skin and hair and resist coming off (retention), visibility of deodorant residue on skin and clothing (visible residue), staining of clothing, irritation and inflammation of the skin, flow resistant to body heat (i.e., the deodorant composition material does not “drip” or “run” appreciably after application), etc.
Often, the base composition materials of deodorant sticks contain gelling agents, which are soluble in vehicle carriers. For example, the vehicle (solvent) is heated in order to dissolve the gelling agent in the vehicle and gelling occurs upon cooling of the composition. In particular, a gelling agent or agents may be selected from high melting point waxes (including beeswax, montan, ozokerite, ceresin, paraffin, synthetic waxes, hydrogenated castor oil); low melting point waxes (including fatty alcohols containing from about 8-20 carbons), and silicone waxes. A more particular group of gelling agents includes stearyl alcohol and hydrogenated castor oil.
For an overall discussion of gelling agents or thickening agents, attention is directed to the solidifying agents described in U.S. Pat. No. 4,919,934 to Deckner, et al., the contents of which have been incorporated herein by reference in their entirety. Examples of such thickening agents include crystalline waxes, cetyl stearate, stearyl stearate, cetyl myristate, cetyl palmitate, stearoxydimethicone, and microcrystalline waxes.